{"paper":{"title":"An \\Al clock with $1.6\\times10^{-18}$ systematic uncertainty and its frequency ratios","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"physics.atom-ph","authors_text":"Christian Lisdat, Derwell Drapier, Erik Benkler, Fabian Dawel, Johannes Kramer, Johannes Rahm, Joshua Klose, Kai Dietze, Kilian Stahl, Lennart Pelzer, Marek Hild, Mirza A. Ali, Navraj Poudel, Piet O. Schmidt, S\\\"oren D\\\"orscher, Stefan Weyers, Steven A. King, Vincent Barb\\'e","submitted_at":"2026-06-22T10:52:11Z","abstract_excerpt":"Advances in optical clocks motivate a redefinition of the second, requiring rigorous evaluations of systematic uncertainties and robust consistency among the clocks. Here, we report the full evaluation of the systematic frequency shifts of an \\AlP single-ion clock, and the measurement of its absolute frequency and frequency ratio with a \\Sres optical lattice clock at PTB. The evaluated total systematic fractional frequency uncertainty is \\num{1.6e-18}, mainly limited by the accuracy of the relevant atomic coefficients and by background gas collisions. The absolute frequency of the clock has be"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2606.23151","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2606.23151/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}